Carding machine sliver and lap stop motion apparatus



4, 1966 J. P. SCARBOROUGH 3,276,030

CARDING MACHINE SLIVER AND LAP STOP MOTION APPARATUS Filed Dec. 23, 1963O) O N INVENTOR.

N Joseph P Scurboroug United States Patent 3,276,080 CARDIN G MACHINESLIVER AND LAP STOP MOTION APPARATUS Joseph P. Scarborough, 1217 RoyallAve., Goldsboro, N.C. Filed Dec. 23, 1963, Ser. No. 332,457 6 Claims.(Cl. 19.25)

The present invention relates to textile carding machines andspecifically to an apparatus for stopping. the carding process uponcertain defects or a breakage occurring in the web or sliver or upon thelap running out.

In the operation of conventional carding machines such as the Model Hmade by the Whitin Machine Works of Whitinsville, Massachusetts, onwhich the present descrip tion is based, it is known that if the web orsliver breaks or if it becomes bunchy, too heavy, or too light or ifforeign matter gets intermingled with the web or sliver, it is desirableto stop the carding process and clear the defect whatever it might bein. order to minimize the amount of defective sliver coming out of thecalender rolls. Another reason for stopping the carding process developswhen the lap runs down to about one-half to one and one-half yards fromthe lap end. This is because the tail end of the lap usually containsoil and sometimes foreign matter and is frequently of a diiferent weightand evenness from that found in the bulk of the lap. Therefore, it isdesirable when the tail end of the lap is reached to stop the cardingprocess, remove the tail end of the lap in process and start a new lap.Aside from other considerations it is known that there is a real risk ofdamaging the card elements if the last yard or soof the tail end of thelap is allowed to go through the lap feed roll. One other aspect of cardprotection that should be mentioned is the fact that when the web orsliver breaks before the lap has run out it is desirable to restore theweb and sliver flow through the calender rolls without disturbing thelap. However, when the lap runs out, it is deemed best practice to breakthe web and sliver and start a new flow of web and sliver at the sametime a new lap is started to insure that the lap end does not becomesliver work product.

Prior art apparatus for protecting the web and sliver flow has usuallytaken the form of a pivoted trumpet through which the web flows andwhich is designed to fall and cause the drive belt to shift to an idlepulley whenever a defect occurs in the web. Other forms of sliverprotection have been employed however the pivoted trumpet concept isprobably the most widely employed type. The conventional pivoted trumpetdevices nevertheless have certain shortcomings in that the operatorusually has to use one of his hands for holding the trumpet in placewhile it is being threaded after clearing a defect whereas thepreferable device would be one that leaves both hands free formanipulating the web into the trumpet entrance. Conventional trumpettype sliver protectors lack means for shifting the belt independent ofthe mean connected to the trumpet which means that the web must bebroken when the belt is shifted. It is also known that some sliverprotectors of the pivoted trumpettype interfere with operation of thedoffer knock-off lever and in some cases even prevent use of the dofferknock-off lever. Recognition should also be made of the difficulty ofgetting a tfine sensitivity in those types of trumpet protectors whichemploy different size trumpet inserts as a means of getting a fineadjustment in sensitivity.

So far as lap run out protection apparatus is concerned some attemptsare shown in the prior art including a form of pneumatic control. In anyevent there has been no widespread acceptance of any form of l-ap runout protection. More specifically the conventional lap run Patented Oct.4, 1966 out apparatus does not connect lap run out and sliver protectionsuch that when the lap runs out the web is also made to part and thetrumpet to fall.

With the foregoing in mind a general object of the invention is toprovide an improved protection apparatus for carding machines to preventcard damage and production losses.

Another object is to provide an improved sliver protection apparatus ofthe pivoted trumpet type.

Another object is to provide an improved lap run out protectionapparatus. 7

Another object is to provide an apparatus which combines protectionagainst web and sliver defects and lap run out.

Another object is to provide an improved sliver protection apparatuswhich can be made extremely sensitive to those types of web and sliverdefects normally encountered in the carding process.

Another object is to provide an improved sliver protection apparatus ofthe pivoted trumpet type Which incorporates means for shifting the drivebelt without disturbing the trumpet position.

Another object is to provide a combined web and sliver defect and laprun out protection apparatus in which la-p run out effects a stoppage ofthe lap and a breakage of the sliver.

The above and other objects will become apparent as the descriptionproceeds and in the drawings, in which:

FIGURE 1 is an isometric skeleton view of some of the principal elementsof a carding machine and showing an embodiment of the invention arrangedwith these elements.

FIGURE 2 is an enlarged isometric view of one of the linkage connectionemployed in the invention.

FIGURE 3 is a partial plan View of the calender roll area illustratinghow the trumpet is adjusted.

FIGURE 4 is an isometric view of a rod connecting member.

The invention is described in reference to the previously mentioned TypeH, Whitin carding machine though it can be applied to carding machinesof other manufacturers. The invention employs a typical trumpet throughwhich the web passes and which is delicately balanced on a pivoted levermechanism connected to a belt shifter. When the trumpet encounters adefect such as abunch area in the web or a web or sliver weight outsideof the range to which the trumpet has been adjusted, the trumpet fallsand effects a shifting of the drive belt which stops the lap feed roll,the lap roll, the doifer, the calender rolls and the coiler rolls. Tothis extent the invention is broadly conventional and no claim is madeto the same except as to the later described and claimed improvementsthereon. I

Departing from the conventional pivoted trumpet apparatus, the inventionprovides a separate linkage to the belt shifter which can be operatedwith the knee and which can be employed to shift the belt withoutdisturbing the trumpet so that other machine adjustments can be madewithout having to interrupt the web and sliver flow through the trumpet.The pivoted trumpet apparatus of the invention also departs fromconventional apparatus of the same type in that a very high degree ofsensitivity and delicate balance is obtained by providing means foradjusting the distance between the face of the trumpet and the centerline of the calender rolls, this adjustment being provided to supplementthe conventional adjustment which depends on shifting a weightincorporated in the pivoting linkage.

Another significant departure is found in the provision for'lap run outprotection. In this regard, the invention recognizes that the positionof the lap pin bears a direct relation to the amount of lap remaining. Alever actuating means is provided which is operated by the lap pinstriking the actuating means and which results in effecting an operationof the belt shifter and in a preferred form also effects an operation ofthe sliver pivoted trumpet apparatus.

Referring in more detail to the drawings in which like numerals indicatelike parts throughout the various figures, in FIGURE 1 the referencenumeral 10 designates a roll of lap material in process, the number 11designates one of the members conventionally provided for supporting aspare lap, not shown, and the number 12 designates the conventional lappin having an extension portion 13 that extends beyond the end of thelap 10 and which is utilized as later described.

The lap feed roll is represented at 15, the doffer cylinder at 16, thecomb at 17, the crushing rolls at 18, the upper calender roll at 19, thelower calender roll at 20, the calender roll stand at,21, the calenderroll stand support at 22 and the calender roll condenser plate at 23.While not shown, it will of course be understood that the feed roll 15,the doffer cylinder 16, the comb 17 which has a vibrating action, thecrushing ll'OiiS 18 and the calender rolls 19, 20 are all provided withthe conventional drive apparatus such that their respective functionsare coordinated with the functions of other conventional parts such asthe card cylinder, flats, lap roll and the like which are not shown butwhich are well understood in the art. That is, the description anddrawings are not intended to represent a complete carding machine butrather only those elements with which the invention is primarilyconcerned and sufficient to teach the invention in one embodiment tothose skilled in the art. To complete this portion of the descriptionthe drive belt 25 is arranged to be shifted between a drive pulley 26and idle pulley 27 and may be driven by an individual or line beltdrive, neither being shown.

As has been previously mentioned, the invention is concerned with bothsliver defect and lap run out protection and the description will nowrefer particularly to the sliver protection. In this regard, the webrepresented at 30 is arranged to pass through a conventional hollow,truncated, horizontally oriented cone shaped trumpet member 31. Onleaving the trumpet 31, the sliver is pulled through the calender rolls19, 20 and emerges as sliver 32 which is directed to the coileirapparatus, not shown. The condenser plate 23 is suitably arranged as atthe indented portion '33 (FIGURE 3) to receive the trumpet 31 such thatthe trumpet exit, when the trumpet is operative, can be placed proximatethe calender roll entrance. With respect to fine balancing of thetrumpet, the invention makes provision for the adjusting screws 40, 41which are threadably mounted in the trumpet 31 and which allow the faceof the trumpet to be moved with respect to the center line of thecalender rolls as represented by the solid line perative position oftrumpet 31 in FIGURE 3 compared to the inoperative dotted line position31. Thus for fine adjustments of trumpet 31, adjusting screws 40, 41 canbe moved in and out and thereby regulate the distance between thetrumpet face and the center line of the calender rolls.

Continuing the description of the sliver protection apparatus, thetrumpet 31 is pivoted on a bent rod member 50 which passes through aspacer 51 secured to rod 50 and is supported in a fixed frame bearingmember represented at 52. Secured to rod 50 is a cantilevered weightstructure 53 and which includes a sleeve 54 secured to rod 50, a rod 55secured to sleeve 54 and a weight 56 adjustably secured to rod 55. Arough balancing can thus be obtained for trumpet 31 by shifting weight56 on rod 55 with a fine adjustment being obtained with previouslymentioned adjusting screws 40, 41.

Rod 50 mounts a further sleeve member 60 which has an integral leverportion 61 containing a hole 62. Lever 61 is connected to an additionalrod member 63 which operates the belt shifter as later explained. It isparticularly important that the conection between rod 63 and lever 61have a minimum of friction and to accomplish this a preferred connectorconstruction is represented in FIG- URES 2 and 4. In particular, anexternally threaded bolt 64 is arranged to be threaded into a femalemember 65. Member 65 has a cylindrical hub portion 66 and integraltherewith a square stern portion 67 having internal threads 68 adaptedto mate with the threads of bolt 64. The hub portion 66 has a hole 69 inwhich rod 63 is positioned as shown in the drawings and once positionedis suitably secured as by the set screw 70. The advantage of this formof connection is that only the four edges of the stem 67 contact theinterior surface of hole 62 and thus lint and other foreign matter whichinevitably collects in this particular area of the machine during thecarding operation is unlikely to substantially increase the friction atthe connection.

Rod 63 is pivotally connected at 75 to an L-shaped member 76 which inturn is pi-votally supported at 77 on a post member 78. Post 78 ispositioned on a pair of horizontally disposed fixed rods 80, 81 whichare supported at one end by a pair of fixed plate members 82, 83 securedto the machine frame, not shown, and are supported at the opposite endon a fixed post member 84- secured by suitable means not shown to themain machine frame. Member 76 has a further pivotal connection at 85 toa rod 86 which is operated by the lap run out mechanism later describedand also has a pivotal connection at 87 to a rod 88 which actuates theforked belt shifter member 89. Belt shift 89 is slida'bly mounted on thetwo rods 80, 81 such that it can be moved laterally to effect a shiftingof the drive belt 25 from the drive pulley 26 to the idle pulley 27.When moved toward the drive pulley 26, shifter 89 tends to compress acoil spring which is loosely mounted on rod 80, and whose purpose isdiscussed later in the description.

From the description thus far, it will be seen that a positiveconnection is made between the trumpet 31 and the belt shifter 89 suchthat the position of trumpet 31 can be used to control the position ofbelt shift 89. With the weight 56 and the screws 40, 41 properlyadjusted an extremely sensitive sliver protection system is established.Of special interest is the fact that when trumpet 31 is positioned foroperation, the lever 61 and rod 63 are brought down to the solid lineposition shown in FIGURE 1 against the tension of spring 95 such thatrod 63 is substantially resting on sleeve 60 and exerting almost zeromoment of force on rod 50. A very slight movement of trumpet 31 howeveras might arise by a change in web or sliver weight or by a bunched webattempting to go through trumpet 31, will disturb this equilibrium andallow lever 61 to move up which puts a moment on rod 50 that isamplified by the tension in spring 95. This then tends to cause a rapidmovement of belt shifter 89.

Once the web and sliver is broken, trumpet 31 has nothing to support itand will remain in the tripped posi tion indicated in dotted lines 31and rod 63 will remain in the dotted line position 63'. In order torestart the carding process it is of course necessary to put the trumpetback into its normal operating position and start the web and sliverback through the trumpet. This is an operation which at the leastrequires expert and experienced hands since it is difficult to use onehand to hold the web and form it into a pointed end for feeding into thetrumpet to form the sliver and use the other hand to hold the trumpet inposition. The invention provides a unique system for assisting in thisoperation in providing a separate trumpet position holding mechanismwhich can be operated by the :operators knee to hold the trumpet inposition thus leaving both the operators hands free to manipulate theweb and sliver. This mechanism includes a T-shaped bar which has ahorizontally disposed member 101 adapted to be engaged by the operatorsknee and which is integral with a somewhat square shaped rod 102 thathas a round rod integral extension 103. That is, member 101, rod 102 androd 103 form the integral structure 100 with the rod portion 102 beingmounted to slide in a fixed plate member 104 suitably secured to themachine frame. Rod 103 passes through, in a free slidable relation, anL-shaped member 5 which is made integral with a sleeve member 106secured to rod 50. Member 105 slides on rod 103 and assumes the dottedline position 105' when trumpet 31 is at position 31". A coil spring 107surrounds rod 103 between member 105 and plate 104 and a pin .108 fixedin rod-102 limits the outward travel of the overall T-shaped rod 100. Inoperation, it will be seen that the operator can use his knee to pressin on member 101 and thus hold trumpet 31 in position and at the sametime hold belt shifter 89 in position to hold belt 25 engaged with drivepulley 26 which leaves both hands free to restart the sliver 32 throughthe calender rolls 19, 20.

Another practical need for a completely satisfactory sliver protectionapparatus is recognized by the provision in the invention for means toshift the drive belt 25 independent of the trumpet operated beltshifting means. For example if the operator wan-ts to pick out foreignmatter out of the web before it reaches the trumpet it should bepossible for him to do so without having to break the web itself. Thisfeature is not provided by conventional apparatus in which the belt canbe shifted only by the trumpet operated shifter. Referring further toFIGURE 1, there is provided a bent lever 120 which pivots on a suitablefixed pin .121 and which connects through a belt 122 to a cable 123entrained around pulleys 124 and 125. Cable 123 is in turn connected toa suitably bent lever 126 which pivots on a pin 12'] and which has abelt engaging portion 128. It will be seen that when lever 120 is pushedin by the hand or knee, lever 126 is pivoted in a manner to cause belt25 to shift to the idle pulley 27 but without disturbing the web orsliver. The travel of lever 120 is limited by a suitable stop member 129that is secured to plate 104.

The description thus far has dealt with the linkage by which the fall ofthe trumpet causes the drive belt to shift, the linkage by which theoperator can use his knee to hold the trumpet in operating position andthe linkage by which the operator can shift the drive belt withoutdisturbing the drive belt shifter linked to the trumpet. The descriptionnext turns to the lap run out protection means. For this purpose, rod 86passes loosely through a hole at 1 50 provided in a verticallypositioned angle member 151 which is pivoted at 152 on plate member 153fixedly secured to the machine frame. In order that rod 86 can beoperated manually for purposes later described, the end which extendsthrough angle member 151 is bent in the form of a handle as shown at 154and a suitable washed 155 is loosely mounted on rod 86 adjacent handle154.

A bent plate member 160 is secured to a pawl member 161 which is pivotedat 162 on angle member 151. Mem her 160 is provided with a V-shapednotched portion 163 and is so arranged with respect to the conventionalextension portion 13 of lap pin 12 that as the lap 10 is depleted theextension portion 13 will gradually move down and engage the notchedportion 166 of member 160. Two means are provided to give pawl 161 apositive inoperative position which means include a spring 165 securedat one end to the frame by suitable means, not shown, the other end ofthe spring 165 being in engagement with pawl 1 61 such that spring 165always tends to lift pawl 161 with the travel of pawl 161 being limitedby an inverted U-shaped member 166 fixedly secured to the frame by meansnot shown. As lap 10 becomes depleted it will be seen that the extensionportion 1 3 will gradually move down, will engage the notched portion116 3 of member and will cause pawl 161 to move down against the tensionof spring 166.

As lap 10 becomes depleted and pawl 161 moves down, the end 176 of pawl1'61 engages a cam which is mounted on the end of the feed roll 15 andwhich rotates with the feed roll 15. Therefore, as lap 10 becomesdepleted cam 175 effectively feels the position of pawl 161 on eachrevolution of feed roll 15 and whenever member 161 is moved downsufiiciently by reason of lap 10 being depleted, earn 175 will causepawl 161 to move outward or rearwardly. As member 161 moves outward,angle member 151 will bear against the handle portion of rod 86 and willcause rod 86 to rotate member 76. As member 76 is moved, all of thelinkage associated with trumpet 3 1 and belt shifter 89 is moved whichcauses trumpet 31 to start falling and the drive belt 25 to be shifted.Since any small shaft in the trumpet 31 position causes trumpet 31 tofall, the belt shifting will be completed by reason of trumpet 3 1falling to its inoperative position 31". That is, a depletion of lap 10causes trumpet 31 to move as if it had encountered a sliver defect andconsequently the linkage between cam 17-5 and trumpet 31 onceestablished need give trumpet 31 only a relatively small movement toaccomplish a shifting of belt 25. From an operating viewpoint, it shouldalso be noted that if the operator is near the lap he can stop thecarding process simply by pulling on handle 154. That is, the lap run'out linkage inherently provides a means to shift the drive belt fromthe lap end of the machine.

As has already been explained, it is desirable when the lap runs out tores-tart the web and sliver since the lap trailing end usually has oiland various foreign matter not conducive to making satisfactory sliver.Thus, by breaking the web and sliver when the lap runs out the operatoris automatically reminded of the need to and in fact is required toclear the old web and sliver. It is possible of course to use the laprun out mechanism with enough throw to shift the shifter 89 whateveramount is required. It is also recognized that many of the inventionsadvantages might be realized by using one belt shifting linkageconnected to the lap run out mechanism and another belt shiftingmechanism linkage connected to the trumpet sliver protection mechanismsuch as the independently operating mechanism connected to lever (126.

Having described the invention, what is claimed is:

1. In a textile carding machine for conversion of fibrous material fromlap to sliver form and having drive and idle pulleys, a drive belt, ashifter for shifting said belt between said pulleys, a trumpet arrangedto receive and condense a web into .a sliver, first linkage meanspivotally mounting said trumpet and connecting said trumpet and shifterto automatically effect said shifting upon said trumpet encounteringcertain predetermined sliver defects, a driven lap feed roll, a lap pinmounting a lap and movable downwardly as said lap is depleted, theimprovement comprising, in combination, a cam mounted on one end of saidfeed roll and rotatable therewith and second linkage means connected tosaid belt shifter and arranged to be actuated by said lap pinestablishing an operative relation between said second linkage means andsaid cam upon said lap pin reaching some predetermined low position toalso automatically effect said shifting when the lap depletioncorresponds to said position.

2. In a textile carding machine for conversion of fibrous material fromlap to sliver form and having drive and idle pulleys, a drive belt, ashifter for shifting said belt between said pulleys, a trumpet arrangedto receive :and condense a Web into a sliver, first linkage meanspivotally mounting said trumpet and connecting said trumpet and shifterto automatically effect said shifting upon said trumpet encounteringcertain predetermined sliver defects, a driven lap feed roll, a lap pinmounting a lap and movable downwardly as said lap is depleted, theimprovement comprising, in combination, a cam mounted on one end of saidfeed roll and rotatable therewith, a follower arm normally positionedout of contact with said cam and so arranged that said lap pin brings itinto operative relation with said cam upon said lap =pin reaching somepredetermined low position, and second linkage means connecting said armto said shifter to also automatically effect said shifting when the lapdepletion corresponds to said position.

3. In a textile carding machine as claimed in claim 2 wherein saidsecond linkage means connecting said arm to said shifter includes ahandle equipped connecting member located proximate said lap andarranged for a manual shifting operation independent of said automaticshifting thereby enabling said shifter to be manually shifted from thelap end of said machine and independent of lap depletion.

4. In a textile carding machine for conversion of fibrous material fromlap to sliver form and having drive and idle pulleys, a drive belt, ashifter for shifting said belt between said pulleys, a trumpet arrangedto receive and condense a web into a sliver, first linkage meanspivotally mounting said trumpet and connecting said trumpet and shifterto automatically effect said shifting upon said trumpet encounteringcertain predetermined sliver defects, a lap pin mounting a lap andmovable downwardly as said lap is depleted, the improvement comprising,in combination, second linkage means connected to said first linkagemeans and arranged to be actuated by said lap pin at some predeterminedlow position thereof sufiicient to trip said trumpet and cause saidtrumpet to fall and to automatically effect said shifting when the lapdepletion corresponds to said position.

5. In a textile carding machine for conversion of fibrous material fromlap to sliver form, in combination, drive and idle pulleys, a drivebelt, first and second independently operable belt shifters for shiftingsaid belt between said pulleys, a trumpet arranged to receive andcondense a web into a sliver, first linkage means pivotally mountingsaid trumpet and connecting said trumpet and first shifter toautomatically effect said shifting upon said trumpet encounteringcertain predetermined sliver defects, calender rolls, a condenser plateproximate said rolls, adjustable screw means mounted in said trumpet andengageable with said plate thereby enabling the position of said trumpetto be finely adjusted with respect to said rolls, bar means connected tosaid first linkage means and adapted to be engaged by the operators kneefor holding said trumpet in its operative position, a manually operablelever mounted proximate and operable independent of said bar means,second linkage means connecting said second shifter and said leverthereby enabling manual shifting of said belt without disturbing theposition of said trumpet, a driven lap feed roll, a cam mounted on oneend of said feed roll and rotatable therewith, a lap pin mounting a lapand movable downwardly as said lap is depleted, a follower arm normallypositioned out of contact with said cam and so arranged that said lappin brings it into operative relation with said cam upon said lap pinreaching some predetermined low position, and third linkage meansconnecting said arm to said first shifter to automatically effect saidshifting when the lap depletion corresponds to said position.

6. In a textile carding machine for conversion of fibrous material fromlap to sliver form and having drive and idle pulleys, a drive belt, ashifter for shifting said belt between said pulleys, a lap feed roll, alap pin mounting a lap and movable downwardly as said lap is depleted,the improvement comprising, in combination, a cam mounted on one end ofsaid feed roll and rotatable therewith, a follower arm normallypositioned out of contact with said cam and so arranged that said lappin brings it into operative relation with said cam upon said lap pinreaching some predetermined low position, and means connecting said armto said shifter to automatically effect said shifting when the lapdepletion corresponds to said position.

References Cited by the Examiner UNITED STATES PATENTS 457,354 8/1891Lawry 19.25 461,171 10/1891 Meats l9.2 493,870 3/1893 Lawry 19-.24582,991 5/1897 Walsh 19.25 1,450,044 3/1923 Morris l9.2 2,554,104 5/1951Hand 19-.25 X 3,167,819 2/1965 Bradburn l9.25

FOREIGN PATENTS 14,582 1896 Great Britain.

MERVIN STEIN, Primaly Examiner.

DONALD W. PARKER, D. NEWTON, I

Assistant Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO.3,276,080 October 4, 1966 Joseph P. Scarborough It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 2, line 35, for "connection" read connections column 4, lines 32and 42, for "shift", each occurrence, read shifter column 5, line 56,for "washed" read washer column 6, line 17, for "shaft" read shiftSigned and sealed this 29th day of August 1967.

(SEAL) Atteat:

ERNEST W. SWIDER I. BRENNER Attesting Officer Commissioner of Patents

1. IN A TEXTILE CARDING MACHINE FOR CONVERSION OF FIBROUS MATERIAL FROMLAP TO SLIVER FORM AND HAVING DRIVE AND IDLE PULLEYS, A DRIVE BELT, ASHIFTER FOR SHIFTING SAID BELT BETWEEN SAID PULLEYS, A TRUMPET ARRANGEDTO RECEIVE AND CONDENSE A WEB INTO A SLIVER, FIRST LINKAGE MEANSPIVOTALLY MOUNTING SAID TRUMPET AND CONNECTING SAID TRUMPET AND SHIFTERTO AUTOMATICALLY EFFECT SAID SHIFTING UPON SAID TRUMPET ENCOUNTERINGCERTAIN PREDETERMINED SLIVER DEFECTS, A DRIVEN LAP FEED ROLL, A LAP PINMOUNTING A LAP AND MOVABLE DOWNWARDLY AS SAID LAP IS DEPLETED, THEIMPROVEMENT COMPRISING, IN COMBINATION, A CAM MOUNTED ON ONE END OF SAIDFEED ROLL AND ROTATABLE THEREWITH AND SECOND LINKAGE MEANS CONNECTED TOSAID BELT SHIFTER AND ARRANGED TO BE ACTUATED BY SAID LAP PINESTABLISHING AN OPERATIVE RELATION BETWEEN SAID SECOND LINKAGE MEANS ANDSAID CAM UPON SAID LAP PIN REACHING SOME PREDETERMINED LOW POSITION TOALSO AUTOMATICALLY EFFECT SAID SHIFTING WHEN THE LAP DEPLETIONCORRESPONDS TO SAID POSITION.